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The goal of the present study was to determine whether 4- and 5-year-old kindergarten children could be trained to maintain an organizational strategy over 2- and 8 week periods through an elaborate training program. A second goal was to assess the effects of the training program on strategy awareness. Twenty-eight kindergarten children were pretested on two sort-recall tasks and their awareness of the use of the clustering strategy was assessed through a protocol type procedure. Half the children received seven half-hour sessions of individual training in the clustering strategy and half the children participated in a control group. Both groups were post-tested on two sort-recall tasks 2 weeks following training and again 8 weeks following training. Strategy awareness, as measured by verbal protocol, was assessed at both post-test points. The elaborate strategy training program was successful in inducing short- and long-term strategy maintenance of the clustering strategy. Trained children’s clustering during sorting and clustering during recall was consistently related to the amount of items correctly recalled. No differences in strategy awareness were found. These findings demonstrate that the elaborate training procedure used in this study can be a very effective memory technique for young kindergarten children.
Dipole moments and various spectroscopic constants of some low-lying electronic states of the CaF molecule have been calculated using the multireference single· and double-excitation configuration-interaction (MRD-CI) method. The electronic structure of the highly ionic molecule in various excited states can be explained in tenns of different polarisations of the mainly Cacentered valence electron in the field of the F\(^-\) anion. Plots of natural orbitals occupied by the valence electron in the different states give a qualitative picture of the charge distribution and provide a visualisation of the different polarisations of the valence electron in the various states. Comparisons with the electrostatic polarisation model ofTörring, Ernstand Kändler (TEK model) are made. The unknown A' \(^2 \Delta\) state is predicted to lie about 21200 cm\(^{-1}\) above the ground state.
Progressive encephalopathy and myopathy in transgenic mice expressing human foamy virus genes
(1991)
Transgenie mice carrying the bel region of human foamy retrovirus (HFV) under transcriptional control of its own long terminal repeat expressed tbe transgene in their centrat nervous systems and in smootb and striated muscle tissues. The animals developed a progressive degenerative disease of tbe centrat nervous system and of the striated muscle. Because expression of tbe transgene was dosely correlated witb the appearance of structural damage and inflammatory reactions were scanty, the disease is likely to be caused directly by tbe HFV proteins. These unexpected findings call for a reevaluation of tbe patbogenic potential of HFV in humans.
The effects of 19 meals of different caloric content on slides on palatability and hypothetical duration of consumption were investigated in 7 patients with anorexia nervosa, 17 patients with bulimia nervosa at the beginning and after 8 weeks of hospital treatment. Nine healthy females served as controls. At the beginning of treatment, palatability of low caloric food was significantly higher and hypothetical duration of consumption of high caloric food was significantly longer in patients when compared to controls. After 8 weeks, in the patients palatability of low caloric food had decreased. Dislike for high caloric food remained stable in anorexics.
A total of 16 Escherichia coli 06 strains isolated from cases of extraintestinal infections were analysed for the genetic presence and phenotypic expression of fimbrial adhesins ( P, S/FIC, type I), aerobactin and hemolysin. ln addition restriction fragment length polymorphisms (RFLPs) of Xbal-cleaved genomic DNA of seven selected strains, separated by orthogonal field alternation gel electrophoresis {OFAGE) were determined and virulence-associated DNA probes were used for Southern hybridization studies of the Xbal-cleaved genomic DNAs. The virulence characteristics and hybridization patterns obtained differed between the various isolates. ln three isolates hemolysin genes and P fimbrial determinants were located on the same Xbal fragments. Furthermore, multiple copies of FIC determinants (foc) could be detected in two strains. Our data show that the new technique of pulse field electrophoresis tagether with Southern hybridization represents a powerful tool for the genetic analysis of pathogenic bacteria.
Thylakoid and cytoplasmic membranes of the cyanobacterium Syncchocystis sp. PCC 6803 were purified by sucrose gradient centrifugation. Both membranes oxidize NADH in a rotenone-sensitive reaction. Antibodies prepared against psbG/ndhKand ndhJ fusion proteins detect the corresponding polypeptides in both membrane preparations. This demonstrates that a NADH-dehydrogenase, homologous to the mitochondrial NADHubiquinone-oxidoreductase (complex I of the respiratory chain) is present in cyanobacteria, The NADH-dehydrogenase can be solubilized with the detergent /-D-dodecylmaltoside. Sedimentation analysis of the solubilized enzyme on a sucrose gradient indicates that it is a multisubunit protein complex.
The legiolysin gene (lly) cloned from Legionella pneumophila Philadelphia 1 confers the phenotypes of hemolysis and browning of the culture medium. An internal Uy-specific DNA probe was used in Southern hybridizations for the detection of Uy-specific DNA in the genomes of legioneUae and other gram-negative pathogenic bacteria. Under conditi9ns of high stringency, tlie Uy DNA probe specifically reacted with DNA fragments fr9m L. pneumophiüz isolates; by reducing stringency, hybridization was also observed for all other Legionella strains tested. No hybridization occurred with DNAs isolated from bact~ria of other genera. The Uy genewas mapped by pulsed-field gel electrophoresis to the respective genomic Notl fragments of Legionelltz isolates. By using antilegiolysin monospecific polyclonal antibodies in Western blots (immunoblots), Lly proteins could be detected only in L. pneumophila isolates.
Effect of inhalation exposure regimen on DNA binding potency of 1,2-dichloroethane in the rat
(1991)
1 ,2-Dichloroethane (DCE) was reported to be carcinogenic in rats in a long-tenn bioassay using gavage in com oil (24 and 48 mg/kg/day), but not by inhalation (up to 150-250 ppm, 7 h/day, 5 days/week). The daily dose metabolized was similar in the two experiments. In order to address this discrepancy, the genotoxicity of DCE was investigated in vivo under different exposure conditions. Fernale F-344 rats (183-188 g) were exposed to [1,2-14C]DCE in a closed inhalation chamber to either a low, constant concentration (0.3 mg/l = 80 ppm for 4 h) or to a peak concentration (up to 18 mg/1 = 4400 ppm) for a few minutes. After 12 h in the chamber, the dose metabolized under the two conditions was 34 mg/kg and 140 mg/k:g. DNA was isolated from liver and lung and was purified to constant specific radioactivity. DNA was enzymaticaBy hydrolyzed to the 3' -nucleotides which were separated by reverse phase HPLC. Most radioactivity eluted without detectable or with little optical density' indicating that the major part of the DNA radioactivity was due to covalent binding of the test compound. The Ievel of DNA adducts was expressed in the dose-nonnalized units ofthe Covalent Binding Index, CBI = f.Lmol adduct per mol DNA nucleotide/ mmol DCE per kg body wt. In liver DNA, the different exposure regimens resulted in markedly different CBI values of 1.8 and 69, for "constant-low" and ''peak" DCE exposure Ievels. In the Jung, the respective values were 0.9 and 31. It is concluded that the DNA darnage by DCE depends upon the concentration-time profile and that the carcinogenic potency determined in the gavage study should not be used for low-Ievel inhalation exposure.
A Goldfish Model for Evaluation of the Neurotaxicity of \(\omega\)-Conotoxin GVI A and Screening of Monoclonal Antibodies. ADEYEMO, 0. M .. SHAPIRA, S., TOMBACCINI, D., POLLARD, H. 8 .• FEUERSTEIN, G .. AND SIREN, A-L. ( 1991 ). Toxicol. App/. Pharmaco/. 108, 489-496. The neurotoxicity of \(\omega\)-conotoxin (\(\omega\)-CgTx), a potent neuronal voltage-sensitive calcium channel blocker, was measured using a new bioassay. \(\omega\)-CgTx was administered intraperitoneally (ip) to goldfish weighing approximately 1.6 g, and dose-related changes were observed over a 2-hr period. \(\omega\)CgTx induced time- and dose-dependent abnormal swimming behavior (ASB) and mortality. The antitoxin activity of the antiborlies was investigated in vivo by either ( l) preincubation of the antibody with w-CgTx at 4°C overnight, or (2) pretreatment with antibody, 30 min before \(\omega\)CgTx injection in a 10:1 antibody/\(\omega\)-CgTx molar ratio. The LD50 dose of \(\omega\)-CgTx in goldfish was 5 nmol/kg ip, and preincubation of monoclonal antibody (50 nmol/kg ip) with \(\omega\)-CgTx (5 nmol/kg ip) significantly (p < 0.05) reduced mortality. ASB, and toxicity time. The antitoxin activity of the monoclonal antiborlies evidenced in the goldfish bioassay was further tested in the conscious rat. In the rat, the increases in mean arterial pressure and heart rate induced by \(\omega\)-CgTx (0.03 nmol/rat icv) were significantly (p < 0.02 and p < 0.0 l, respectively) attenuated by preincubation of the toxin with the antibody (0.3 nmol/rat). We conclude that the goldfish bioassay provides a simple. accurate, and inexpensive in vivo model for the study of the toxicity of \(\omega\)CgTx
The melanoma inducing locus of Xiphophorus encodes a tumorigenic version of a novel putative receptor tyrosine kinase (Xmrk). To elucidate the mechanism of oncogenic activation of Xmrk, we compared the structure and expression of two oncogenic loci with the corresponding proto-oncogene. Only minor structural alterations were found to be specific for the oncogenic Xmrk genes. Marked overexpression of the oncogene transcripts in melanoma, which are approximately 1 kb shorter than the proto-oncogene transcript, correlates with the malignancy of the tumors. The tumor transcripts are derived from an alternative transcription start site that is used only in the oncogenic loci. Thus, oncogenic activation of the melanoma inducing Xmrk gene appears primarily to be due to novel transcriptional control and overexpression.